Center punching assembly



N. J. GOULDSMITH, JR 2,730,81 1

CENTER PUNCHING ASSEMBLY Jan. 17, 1956 Filed April 5, 1954 INVENTOR. /V0e/ J 600/46/27/7/4 BY 4 a! Q 97I0RNEK United States Patent CENTER PUNCHENG ASSEMBLY Noel J. Gouitlsmith, Jr., Independence, Mo.

ApplicationApril. 5, 1954, Serial No. 421,136

2 Claims. (Cl. 33-189) This invention relates. to center punching tools and, more particularly, to any improved center punching as: sembly adapted for use. in Work where an increased degree. of accuracy and reliability is desirable.

It is the. primary object of this, invention to provide a center punching assembly having a work-engaging base provided with a peripherally marked perforation which may be aligned1 with great accuracy over the point. to. be punched by sighting through a magnifying; lens; forming a part of an upper structure swingably mounted on the base and carrying a reciprocable punch.- ing element adapted to extend concentrically through the. perforation when the structure is swung from a viewing position. to a punching position.

Other important objects of the invention, including significant details of construction, will be made clear or become apparent as the following: description of? the invention progresses.

In the accompanying; drawing:

Figure 1 is a top plan view of the center punching. assembly of this. invention with the upper. structure thereof disposed in its punching position relative to. the base;

Fig. 2 is a cross sectional: view taken on line. IL-If: of Fig. 1 and showing in dotted lines the position of the. punching element and the. parts associated therewith when the same: are: reciprocated. in: a direction for ac.- complishinga. punching operation;

Fig. 3 is a cross sectional view similar to that. of Fig. 2 but showing: the. upper structure of the center punching assembly swung" to its viewingor aligning. position;.

Fig. 4 is a view, partially in. cross section andpartially. in. elevation, taken on. irregular line IV-IV of Fig, 2; and

Fig. 5 is a fragmentary, top plan view: ofthatportion: of the base in which the aligning and punching perforation is formed, particularly illustrating the alignment markings provided! on the. walls of such perforation.

Center punching by methods employing types of center punching tools heretofore known has been, at, best, unreliable as to accuracy and subject in large. measure to the experience and ability of. the operator. The improved center punching assembly provided by this. inyention is not only simple in structure, inexpensive to manufacture and fool=proof in use, but further makes it possible for event inexperienced operators to accomplish center punching operations with. greater, accuracy and reliability than has heretofore been feasible in the case of experienced operators using conventional center punching tools.

Referring now to the accompanying drawing the numeral broadly designates a base and the numeral 12 broadly designates an upper structure mounted on base 10 as hereinafter explained.

Base 10 comprises a metallic plate 14 having a workengaging face 16 and a preferably fiat, opposed face 18. In the embodiment of the invention shown for 2,730,811 Patented Jan. 17, 1956 purposes of illustration, face 16is fiat and thereby. adapted. for resting upon and being moved along a flat worl; surface. Obviously, however, face 16 could be arcuate or. of. any other configuration adapted. to. complement the. Work surface with. which the assembly of this. in; vention istobe used.

An. aligning and. punching perforation 2 0 is formed. in p1ate14 and preferably includes a chamfered portion. 22 presenting a frusto-conical indicator surface 24-upon. which a. number of markings. 26. are placed to: aid in. aligning the portion; 28 of perforation 20. nearest. face; 16. of plate. 14 concentrically with respect to. av predetermined point on the work surface to be punched. A protuberance. 3.0. extends laterally from face. 18. of plate, 1,4. and. is. providedwith abore 32 presenting. a bearing. for an elongated. hinge. pin 34 which extends beyond' the extremities. of bore 32 of protuberance 30. Plate. 14, may, also, be. provided, if. desired, with a hole 36'for passing; a screw (not shown), engageable in a threaded: hole 37 of upper structure 12. for securing the. latter in fixed. relation to base. It) when. the assembly. is being stored, shipped or otherwisenot being used.

Upper structure 12 includes a main body member 38, having ahollowed-out portion 40 and an elongated, cylindrical extension 42 provided with an external. surface. 44. A. cylindrical bore. 46 extends longitudinally. through extension 42 and through main body 38- into communication with hollowed-out portion 40.

Main. body portion 38 is provided with a base en.- gaging. surface, 48 disposed in a plane. preferably. perpendicular to the, axis; of bore. 46, such. plane being spaced from. the normally lowermost end 50 of bore 46. Main. body 38 is.also. provided with a second base engaging surface 5,2v disposedwithina plane intersecting the plane of surface 48. and forming an obtuse angle therewith.

Main body 38 includes side walls 54- and 56. each ofwhiehare perforated, as at; 58; to receive pin 3.4, thereby hingedly mounting, structure 12 upon. base 1 0 for swinging movement. between a. punching position placing surface 48 of main body 38 in engagement with. upper face 18 of plate 14 and? an aligning or viewing. position, placing surface 52. of. body 38, in. engagement with upper surface. 1&ofplate14. It is noted that perforations 58 in side. Walls. 54.. and 5.6 are preferably located adjacent. the. zone, of juncture between the planes, of surfaces 48 and 52 in order to place the point of pivot of, structure 12 upon base 10, to one. side of the axis. of, bore 46.

A, viewing opening 60 is formed in body 38 and has its axis. preferably perpendicular to the plane of surface 52, an eyepiece 62. including a magnifying lens. 64. being, mounted in any suitablev manner. within opening, 60.

R'eciprocably mounted within bore 46 is an elongatedpunching element 66 having its lowermost end pointed as at 68 for indenting work tobe punched. Slidably mounted upon surface, 44 of extension 42 is a hollow, cylindrical cap '70 having an inner side wall surface 72; adapted to slide along surface 44. of extension 42, and an upper portion. 74 provided with a bore 76. receiving the uppermost end, of punching element 66, the latter being secured to upper portion 74 of cap 70 by means of a set screw 78. Disposed within cap 70 and hearing at its respective ends against lower portion 74 of cap 70 and the upper extremity of extension 42 is a coil spring 89 for yieldably biasing cap 70 and punching element 66 toward a position withdrawing element 66 from the upper extremity of extension l2. Punching element 66 is provided with a split ring stop means 82 adjacent its lowermost end to limit reciprocation of element 66 under the influence of spring 80.

A suitable impact guard 84 may be provided, if desired, over the upper portion 74 of cap 70 for receiving pressure from the hand of an operator. to reciprocate punching element 66 during operation of the assembly.

In operation, it will be clear that structure 12 is initially swung relative to base to the position illustrated in Fig. 3 of the drawing, which disposes the axis of viewing opening 60 and lens 64 in concentric alignment with the axis of lower portion 28 of perforation 20. The operator, sighting through magnifying lens ,64 and perforation portion 28, moves base 10 to a position exactly aligning the point on the work to be punched concentrically of perforation portion 28, as indicated by markings 26 provided on the indicator surface 24 of perforation 20. It may be noted that when mounting 12 is swung to the above-mentioned viewing or alignment position, light may freely pass between body 38 and plate 14 to render the work underlying perforation portion 28 visible to the operator; however, it will be obvious that auxiliary artificial lighting means within hollow portion 40 of body 38 could be provided in any conventional fashion, if desired.

When base 10 has been so aligned over the point on the work to be punched, plate 14 is held in position upon the work surface and upper structure 12 is swung on the pivot provided by pin 34 to the position illustrated in Fig. 2, which aligns the axis of bore 46 and accordingly the punching point 68 of element 66 concentrically with respect to the axis of perforation portion 28. It may be here noted that any conventional means of the adjustable screw or other suitable type might be provided on body 38 or plate 14 for assuring that the axis of bore 46 is exactly aligned with the axis of perforation portion 28, if desired; however, it is to be preferred that face 18 of plate 14 and surface 48 of body 38 be merely properly machined so as to align the axis of bore 46 with the axis of perforation portion 28 when body 38 is swung on pivot 34 to the position illustrated in Fig. 2.

With upper structure 12 in the punching position just described, the operator may exert appropriate pressure or impact force downwardly upon guard 84 which will slide cap 70 downwardly over extension 42 against the action of spring 80, thereby reciprocating punching element 66 along bore 46 and through perforation 20 moving punching point 68 of element 66 to a work-engaging position, as indicated in dotted lines in Fig. 2, slightly below face 16 of plate 14 to punch the work at the desired point.

It may be noted that bore 46 is preferably presented by a bushing 90 press fitted or otherwise suitably held in place within a larger bore 92 formed in body 38 and extension 42. Bushing 90 provides a wearing surface for slidably receiving reciprocable punch element 66 other than the casting by which body 38 and extension 42 are preferably formed, and may be replaceable, if desired.

It is also significant that edges 94, 96, 98 and 100 of plate 14 are preferably squared with each other and spaced predetermined distances from the center of perforation portion 28, in order that an edge 94, 96, 98 or 100 can be disposed along a line on the work to be punched and element 66 operated to indent a point on the work removed from said line by a distance equal to the predetermined spacing of such edge from the center of perforation portion '28. Merely as an illustrative example, edge 94 may be one inch from the center of perforation portion 28, edge 96 may be one and one half inches therefrom, edge 98 may be one and one-fourth inches therefrom and edge 100 may be one and threefourth inches therefrom; it will be clear that, with such a construction, points may be accurately punched either one inch, one and one-fourth inches, one and one-half inches or one and three-fourth inches from a line on the work and, when parallel blocks (not shown), are also used, a point removed from either or both of a pair of perpendicular lines on the work by respective distances determined by the interposed blocks may be punched with great accuracy.

It will now be apparent that a center punching assembly of greatly improved accuracy and reliability has been provided. It will also be manifest that certain modifications or changes could be made in certain of the structure above described for purposes of illustration without departing from the true spirit or intention of this invention. Accordingly, it is desired that this invention shall be deemed limited only by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A center punching assembly comprising a base plate having a work-engaging face, an opposed, flat face, and a viewing and punch-clearing perforation therethrough; a structure having a pair of contiguous surfaces disposed in obtusely angled planes, a viewing opening therethrough having its axis substantially perpendicular to the plane of one of said surfaces, and a punchreceiving bore therein having its axis perpendicular to the plane of the other of said surfaces; means swingably mounting the structure on the plate for movement between an aligning position and a punching position respectively disposing said one surface and said other surface in parallelism with said flat face of the base and said opening and said bore in axial alignment with said perforation; a magnifying lens mounted in said opening; a punch element; and means reciprocably mounting the element in the bore for movement to and from an operative position extending through said perforation when the structure is in said punching position.

2. In an assembly as set forth in claim 1, wherein a portion of said plate surrounding said perforation is internally ohamfered to present a perimetric indicator surface on said plate in circumscribing relationship to said perforation, said surface being provided with index markings for use in centering the perforation upon a point on the work to be punched.

References Cited in the file of this patent UNITED STATES PATENTS 1,424,941 Pirwitz Aug; 8, 1922 2,167,103 Bustamente et a1. July 25, 1939 2,364,497 Wahnish et a1. Dec. 5, 1944 2,462,573 Turrettini Feb. 22, 1949 2,526,528 Zickler et a1. Oct. 17, 1950 2,599,652 Mitchell June 10, 1952 FOREIGN PATENTS 229,553 Germany Dec. 30, 1910 

